Slice zucchini 1/8" thick on a mandoline or using a sharp knife.
Line a baking sheet with paper towels. Lay zucchini slices flat in a single layer onto the prepared baking sheet. Sprinkle each side with 1/4 teaspoon salt; let stand 15 minutes.
Heat 1 tablespoons of olive oil in a large cast iron skillet (you'll use this pan later to bake the lasagna rolls). Sauté the mushrooms, onions, and garlic together for 4-5 minutes, or until mushrooms and onions have softened and browned.
Pour in the cooking wine, stir, scraping brown bits off the bottom of the pan. Remove pan from heat and allow to cool almost completely. I transferred the mushrooms and onions to a mixing bowl and placed them in the refrigerator to cool quickly so the cheeses didn't immediately melt when added.
In a medium sized mixing bowl, use a fork to combine the mushroom mixture with the ricotta cheese, egg, spinach, salt, and pepper. Then stir in the fresh chopped basil, 1/2 cup mozzarella cheese, and 1/2 cup parmesan cheese.
Spread about ½ cup marinara sauce in a 12'' cast iron skillet.
Begin assembling the zucchini rolls by spreading about a tablespoon of filling on each piece of zucchini. Roll tightly. Place each roll on top of marinara sauce in a baking dish so it's standing upwards. Repeat with the rest of zucchini. If you have extra filling, spread on top of zucchini rolls.
Pour the rest of marinara sauce on top and sprinkle with remaining mozzarella cheese and parmesan cheese.
Place skillet in oven and bake for 25-30 minutes or until lasagna rolls are heated through and the cheese begins to brown.
Top with more fresh basil and cheese, if desired, and serve.
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Notes
* Drain spinach as much as possible. You can even press it in paper towels or a tea towel.